There is a consumer demand for drink dispensing machines, such as coffee machines, that can dispense a variety of drinks in receptacles of different sizes. For example, some coffee machines are capable of preparing an espresso coffee or a lungo coffee in a small or medium cup and a “macchiato” coffee in a large glass.
Multi-beverage machines are capable of preparing coffee, milk, cappuccinos and tea and have dedicated outlets for each drink. For example, CH 685 597 discloses a beverage machine which combines an outlet for coffee, an outlet for milk and a water outlet for tea, all outlets being arranged within a diameter of a user-cup located therebelow so that a user always places a cup onto the same spot whichever beverage, i.e. coffee, tea or milk, he requests.
Brewing systems are for example disclosed in EP 0 730 425, EP 0 862 882, EP 1 219 217, EP 1 480 540, EP 1 545 278, EP 1 635 680, EP 1 659 547, EP 1 669 011, EP 1 721 553, EP 1 774 878, EP 1 776 026, EP 1 893 064, EP 1 912 542, FR 2 424 010, U.S. Pat. Nos. 3,260,190, 4,064,795, 4,760,774, 5,531,152, 6,966,251, 7,131,369, US 2005/0106288, US 2006/0102008, WO 02/074144, WO 03/030696, WO 2005/002405, WO 2005/004683, WO 2005/016093, WO 2005/072574, WO 2005/115206, WO 2006/005736, WO 2006/005756, WO 2006/023309, WO 2006/066626, WO 2007/135136 and WO 2008/037642.
Typically, the existing brewing systems, in particular using pre-portioned flavoring ingredient cartridges, accept a predetermined amount of flavoring ingredient, such as ground coffee or tea leaves, for an extraction cycle to prepare a beverage portion, e.g. for filling a user-recipient such as a cup or a mug. The volume of beverage prepared from such a predetermined amount of flavoring ingredient depends on the amount of liquid circulated through this amount of flavoring ingredient.
For instance, the quantity of water that is recommended for preparing different coffee types varies from coffee to coffee type. Typically, a ristretto requires 25 ml of water. An espresso will normally need between 40 and 60 ml of water. A lighter lungo should be prepared with about 110 ml. A still lighter American-type coffee will require 150 to 300 ml. Hence, the same or similar volume of flavoring ingredient will be used to prepare beverages of significantly different sizes.
A problem to such a beverage preparation configuration is the span of the range of liquid quantity circulated through the same volume of flavoring ingredient. For large size beverage preparations, there is a risk of over-extraction of the flavoring ingredient whereby undesirable compounds end up being washed out of the flavoring ingredient by the large amount of extraction liquid and impair the quality of the beverage. In the case of a coffee preparation, this translates into the extraction of undesired bitter oils from deep inside the coffee ingredient.
A solution to this problem lies in the increase of the amount of flavoring ingredient for preparing large-size beverages compared to small size beverages. This solution is usually implemented to a certain extent in the expensive full-automatic coffee machines that incorporated a coffee bean grinder and a brewing chamber of adjustable size for receiving different volumes of ground coffee.
For machines preparing beverages from pre-portioned flavoring ingredient cartridges, in particular those having an ingredient chamber with a fixed capacity, it would possible to instruct a user to multiply the preparation of small-size beverages using a plurality of cartridges, the small-size beverages being then collected in a single mug for preparing a large-size beverage. However, this puts the burden on the user to adjust the number of cartridges for a given beverage. Moreover, the resulting coffee, i.e. a multiple espresso, may turn out to be significantly stronger than the coffee expected by an American-type coffee drinker.
EP 0 806 168 discloses a coffee filtering apparatus having a hot water circulation line split into a first conduit leading to a presumably conical filter holder with an extraction chamber for ground coffee and into a second conduit by-passing the filter holder. A large coffee pot is fixed via its mouth to the conical filter holder for collecting and storing the prepared coffee, e.g. the equivalent of six cups, dripping from a non-shown opening of the filter holder. The bypass conduit has an outlet that ends over the mouth of the coffee pot when fixed to the conical filter holder. By fixing the large coffee pot to the filter holder, proper positioning is obtained of the mouth of the coffee pot under the filter holder and the bypass conduit.